Measuring and testing – Liquid analysis or analysis of the suspension of solids in a... – Viscosity
Patent
1994-03-02
1995-09-12
Williams, Hezron E.
Measuring and testing
Liquid analysis or analysis of the suspension of solids in a...
Viscosity
G01N 1114
Patent
active
054489083
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention concerns a device for the measurement of the viscoelasticity of products, and particularly those with a low viscosity.
2. Description of the Related Art
It is often necessary when measuring the physicochemical characteristics of a given product, such as a resin, a paint or a plastic, to measure and know the viscoelasticity of the product in question.
A great many devices for measuring viscoelasticity have been proposed. Some consist of two flat plates between which the product to be measured is deposited. An angular movement of one plate in relation to the other creates a shear torque in the product. A measurement of this shear torque serves to determine the viscoelasticity of the product deposited between the plates.
Other devices known under the generic designation of Couette type rheometers have a female cupel into which is put a male cupel, the cupels being cylindrical and the product to be measured being deposited in the female cupel. The product is sheared between the cupels, one of which is fixed and the other mobile.
The theory of rheometers of the Couette type and their structure are described in "Initiation a la Rheologie" (Introduction to Rheology), 1983 edition of "Technique et Documentation" (Lavoisier).
Other devices for measuring the viscoelasticity or rheometers are disclosed in FR-A-2,531,538, U.S. Pat. Nos. 3,667,286 and 2,828,621.
A serious drawback of all rheometers used until now resides in the fact that they operate in the open air. Because of this, when the measuring device is put into a heating cabinet or an oil bath to raise the product or substance to be measured to a designated temperature, which depends, among others, on the nature of the product to be measured, it follows that, in products containing a solvent, the solvent evaporates in more or less large quantities, and this occurs no matter how fast the product is put into the female cupel, or into the heating cabinet or oil bath. However, the evaporation of the solvent leads at least to a change in the physical characteristics of the product. Consequently, the shear torque is affected and this often leads to erroneous results.
Another serious drawback is related to the very structure of known cylindrical rheometers. Such rheometers, in addition to the fact that they are open and thus likely to permit evaporation of solvent, are relatively large in size and necessitate a change of the shear torque measuring sensor whenever there is a change to another product with a different viscosity. This results in an increased risk of damage to sensors which, furthermore, are very expensive. In addition, they are poorly suited to an alternating or sinusoidal movement between the mobile and fixed cupels due to the inevitable inertia caused by the oversizing of the cupels.
SUMMARY OF THE INVENTION
The purpose of this invention is to palliate the above-mentioned disadvantages and to propose a measuring device which is impervious to the ambient atmosphere, of small size and adaptable to presently-used viscoelasticity meters.
An advantage of this invention resides in the fact that the device operates in an impervious medium, without any evaporation of solvent.
Another important characteristic is that several annular chambers are arranged in the female cupel, for the measurement of the viscoelasticity of products with a very low viscosity.
In addition, the device under this invention is provided with means for the direct introduction of products into the female cupel, which prevents any evaporation of solvent when the product to be measured is put into the female cupel.
Other advantages and characteristics are to be understood more clearly on reading the description of a preferred design of the invention, as well as the appended drawing.
BRIEF DESCRIPTION OF THE DRAWING
The only FIGURE is a sectional view of the measuring device according to a preferred embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The device under the invention includ
REFERENCES:
patent: 2096222 (1937-10-01), Bock
patent: 2828621 (1958-04-01), Rosenberg
patent: 3350922 (1967-11-01), Kim et al.
patent: 4214475 (1980-07-01), Carter et al.
El Bounia Nour-Eddine
Rey Cathy
Brock Michael J.
Societe Nationale Elf Aquitaine
Williams Hezron E.
LandOfFree
Device for the measurement of viscoelasticity of products, and p does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device for the measurement of viscoelasticity of products, and p, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device for the measurement of viscoelasticity of products, and p will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-400393